The importance of sleep for learning and remembering

Most often when we talk about learning and remembering, what we are discussing is our ability to extract information from our memory – or our ability to recall information. However, this is just one of the three necessary phases that we use when we are learning and remembering. Knowing about the other two phases can help us to learn and remember better. What are the other phases?

Phase 1 – Encoding new information

As we learn new information, we have to create new connections that store the information in our heads. Our memories are stored throughout the brain in networks of neurones that are continually active. These networks connect up all of the information that we have learnt and remember about a particular topic. Take, for instance, cats. The network of connections for cats might contain an image of a typical cat, an image of a pet cat (or two), the sound a cat makes, breeds of cats, whether you like cats or not, the feel of cat fur when you stroke a cat, the feel of a cat’s claws when you are scratched by a cat. All of this information can be accessed as you begin to spend time thinking about cats.

The richness of your memory for cats will depend on the number of cats you have encountered in your life, your preference for cats, and the number of different senses that you have used to code information about cats. The more senses you use to code information, the easier it becomes to retrieve you memory of cats. This is because all of the information stored can be activated by any part of it. So you might start thinking about cats if you feel some fur that reminds you of stroking a cat, if you hear a sound that reminds you of a cat purring, if you see an image of a cat or if you smell something that you have linked to cats.

The more richly we code information, the easier it is to recall and our memory is sometimes poor, not because we cannot remember, but because we did not code the information richly enough in the first place.

To improve this, start to notice more about each experience you want to remember. Repeat a story of the experience with as much sensory detail as you can remember. It will make the memory more intense and easier to retrieve.

Phase 2 – Consolidating new information

We use the same parts of the brain to code new information and to recall past information so our memory circuits are constantly active. However, the second phase of making new memories needs to use these circuits for an additional use. When we are coding new experiences or information, the brain incorporates this into our previous memories. This phase is called consolidation of memory and it is vital to making strong, long lasting memories.

If we cannot consolidate when we are using our memory circuits to code and recall, when do we consolidate new information? This is done while we are asleep. Part of this process creates our dream states which often contain both things that we have encountered recently and experiences, people and places from our past.

If sleep is important for consolidation, it might be useful to know how much sleep you ned to consolidate. The answer is quite surprising. Depending on the complexity of the information we are trying to learn, we need about 6 minutes of sleep to consolidate this.

To improve our memory for new information that we are trying to learn, this suggests that we should have either a short nap after learning new material, or that we should learn just before we go to sleep at night. This will ensure that the new information is properly consolidated into our memories making these longer lasting.

So, if you would like to improve your memory, use these two top tips:

Get better at coding information but making it as rich and multisensory as possible

Make sure you have some sleep after learning something new

This blog is based on the following references:

Chee, M.W. & Chuah, L.Y. (2008). Functional neuroimaging insights into how sleep and sleep deprivation affect memory and cognition. Current Opinion in Neurology, 21, 417-423.
Maguire, E., Valentine, E., Wliding, J. & Narinder, K. (2003) Routes to remembering: the brains behind superior memory. Nature Neuroscience, 6, 90-95.

By Patricia Riddell, Consultant Neuroscientist